Reader: Where in the Torah does it instruct man that allowed animals must undergo Shechita? Secondly, the Talmud has reinterpreted God’s word to allow for the business of Shechita by trained men. This fact has not only added to but also diminished from the words found in Torah. Is this interpretation by men in Talmud changing the words of God?
Mesora: Talmud Yoma 75b states: “Rebbe said [the words] ‘and you shall slaughter as I commanded you’ (Deut. 12:21) teach that Moses was commanded on the food pipe and the wind pipe; that the majority of one [pipe] must be cut in fowl, and the majority of both [pipes] regarding beasts.”
We learn from here that when God commanded Moses in Deuteronomy to slaughter “as He commanded”, there was an accompanying instruction in the Oral Law concerning just how Shechita is to be performed “as He commanded”. The Talmud transmits this Oral Law to us.
Regarding your second question, one may slaughter his animals himself - he need not hire another. As well, he may create his own Tefillin. But to create Torah-recognized forms of these and other objects of Mitzvah, much knowledge is required. Therefore, one who is relatively ignorant of the Torah’s prescribed design and creation of objects of Mitzvah is wise to pay another to create them for him. I see no reason why one cannot make his business the creation of Torah scrolls, Tefillin, Succahs, or performances, like Torah reading, circumcision, or Shechita. There is no law prohibiting the taking of money to assist another…even in areas of Mitzvah. Be mindful, the one paying the professional is doing so willingly.